My friend Derek, who's the dev lead for MSXML (the XML toolkit used by practically every Microsoft application from Office to Internet Explorer), has a blog post entitled XML use in the browser where he writes

C|Net has an article on what people have started calling AJAX. 'A'synchronous JavaScript and Xml. I have seen people using MSXML to build these kinds of web-apps for years, but only recently have people really pulled it all together enough, such as GMail or Outlook Web-Access (OWA). In fact, MSXML's much copied XMLHTTP (a.k.a. IXMLHttpRequest) (Copied by Apple and Mozilla/Firefox) was actually created basically to support the first implementation of OWA.

I've been thinking about what our customers want in future versions of MSXML. What kind of new functionality would enable easier/faster developement of new AJAX style web applications? XForms has some interesting ideas... I've been thinking about what we might add to MSXML to make it easier to develop rich DHtml applications. XForms is an interesting source of ideas, but I worry that it removes too much control. I don't think you could build GMail on XForms, for example.

The most obvious idea, would be to add some rich data-binding. Msxml already has some _very_ limited XML data-binding support. I have not looked much into how OWA or GMail work, but I bet that a significant part of the client-side jscript is code to regenerate the UI from the XML data behind the current page. Anyone who has used ASP/PHP/etc is used to the idea of some sort of loop to generate HTML from some data. What if the browser knew how to do that for you? And knew how to push back changes from editable controls? You can do that today with ADO.

Any other ideas? For those of you playing with 'AJAX' style design. What are the pain points? (Beside browser compatibility... )

If you are building applications that use XML in the browser and would like to influence the XML framework that will be used by future versions of Microsoft applications from Microsoft Office to Internet Explorer then you should go over to Derek's blog and let him know what you think.